Chisles - Design and Construction (long)

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Oct 22, 2012
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I know it's not strictly knife making, but I'm hoping to produce some handmade chisels for my personal use (and if goes well, for sale), and I'm looking for some input and advice. I also have a more general thread on chisels over in Gadgets and Gear, if anyone just has advice on chisels in general.

I would like to make woodworking chisels rather than the rock-busting type, but all sorts will follow if I am successful. Now I'm looking into wood and all-around chisels for around the house use.

I would like to know:

Are chisels zone-tempered, or are they hardened to the same level throughout? I know Japanese chisels are treated up to 65HRc, but most cheaper western (read: Chinese-made), when listed, seem to be in the mid 50s HRc. Again, I don't know if this is just on the edge, but it would seem practical to me to treat a little softer for a chisel that would be multi-purpose, with the edge a little harder for longer lasting edges. What do you guys recommend for a temper on a fine chisel?

What steel would you like to see in a handmade chisel? A2 or plain carbon seems standard, with proprietary alloys also common. It seems that D2 is on the high-end for western woodworking chisels. Traditional Japanese chisels are made with plain carbon White steel, with some higher end examples made from Blue and Super Blue steels. I was thinking 3v would be a great candidate for a chisel, given it's toughness. I'll likely start with 1084 or 01 for ease of HT, but hopefully move on to higher-alloy steels like 3v and M4 if I get the kinks worked out. Any perspective or suggestions are welcome.

Handles. What should I make them from? Wood is nice, and looking good is a large part of fine tools, but I really want these tools to take as much abuse as can be reasonably expected, so I was thinking of synthetics. G10 or the high-end acrylics I've seen (many look marbled or glow in the dark) would seem to be great candidates if I could find suitable blocks, and would likely be just as easy to work, stable and strong as the densest, most stabilized woods. Of course, I could always offer wood as an option. I worry that, even with top of the line steel and tolerances, a synthetic handle would lessen the appeal of fine tools, and would give a "cheap" feeling to some customers. Thoughts?

Handle construction is also a point of contention. I would like to design "full-tang" handles with a long shank, like this:
STA016253.jpg


It seems to me to give strength and balance that a shorter tang would lack. It should be easy enough, with or without a gap between the butt of the chisel for shock absorption.

Lastly, there are a few blade designs I have been debating. Should the sides taper up to make a sort of triangle cross-section, like this:
s309565.jpg

Or is there some advantage to a more traditional shape, like this:
101-6732_lrg.jpg


Ok guys, I hope I still have at least one reader at this point, and I would appreciate any recommendations.
 
For the tops in handmade chisels, try W2 or Hitachi blue paper#2 .

Harden and temper for Rc63-64. Then draw the tang and shank back. The edge can be left very hard on chisels that will be used right. If the chisel will be abused, get one from the dollar store :) .
 
Thanks, I suppose I will begin and end with W2 then, since it's much easier for me to get and afford than Hitachi steel. I am still curious as to how the upper-echelon tool steels would fare, but that would be an expensive experiment.
 
Chisels are fine edge cutting tools. While CPM-M4 might be harder and tougher, it would not have the edge fineness needed for a top grade chisel. A hyper-eutectoid steel with just a bit of alloy will get a very fine edge. That description describes W2 very well.

Edge fineness is largely a matter of the grain size and the carbide size.
 
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